Extrusion wrapping deflector

ABSTRACT

A method for wrapping a stream of material or stream of layers of materials includes feeding a stream of material or stream of layers of materials into a die containing a wrapping deflector which acts to wrap the stream into a tubular or profile shape.

FIELD

The present disclosure generally relates to extrusion die systems. Inparticular, the present disclosure relates to wrapping tubular extrusionof one or more stream(s) to generate new geometries. The products ofthese wrapped streams and layers may contain small sized grain features,in the range of mili, micro and nanosized grain features, in a tubularor profile shape.

BACKGROUND OF THE INVENTION

Extrusion technologies are well known in the art including those methodsdescribed in U.S. Pat. Nos. 6,669,458, 6,533,565 and 6,945,764, and arecommonly owned by the assignee of the instant application. Micro-layerextrusion processes are specialized extrusion methods that provideproducts with small grain features such as described in U.S. Pat. No.7,690,908, (hereinafter the “'908 Patent”) and U.S. Patent Publication2012/0189789 (hereinafter the “789 Publication”) both of which arecommonly owned by the assignee of the instant application, thedisclosures of which are incorporated herein by reference in theirentirety.

Typical micro-layer products are formed in a sheet. If a tubular productis desired, the microlayer is first extruded as a sheet and then madeinto the tube. This creates a weld line or separation between themicrolayers. The '908 Patent describes a cyclical extrusion of materialsby dividing, overlapping and laminating layers of flowing material,multiplying the flow and further dividing, overlapping and laminatingthe material flow to generate small grain features and improveproperties of the formed product. The '789 Publication describesextruding a flow of extrusion material in a non-rotating extrusionassembly, forming a first set of multiple laminated flow streams fromthe extruded flow, amplifying a number of the laminations by repeatedlycompressing, dividing and overlapping the multiple laminated flowstreams, rejoining the parallel amplified laminated flows, forming afirst combined laminate output with micro/nano-sized features from therejoining; and forming a tubular shaped micro-layer product from thecombined laminate output. There is still a great need for new extrusiongeometries.

SUMMARY OF THE INVENTION

The purpose of this invention is to provide a unique distribution groovefor a balanced flow passage used to disperse the molten plastic in anextrusion die evenly within a tubular or profile extrusion channel. Thisdistribution groove may also serve to multiply layers contained in astream of molten plastic. Die systems, employing balanced flowdistribution grooves, are constructed by assembling a series ofcylindrical components along a common axis. A continuous flow passage isformed by the cooperation of the adjacent components. Additionally, thisinvention is directed to new components which have multiple applicationsand facilitate the replacement of certain parts of the passage toprovide different functions.

A deflector is a component, which in conjunction with a tip and/or otherdeflectors, acts to perform the shaping of the molten plastic. Themolten plastic would then proceed through the extrusion head in itsnewly formed shape. After any compression or other shape modificationsthe plastic will eventually exit in the desired product shape.

According to the invention, a stream of material or stream of layers ofmaterials may be fed into a die containing a ‘wrapping’ deflector whichwill act to wrap the stream into a tubular or profile shape. Thesedeflectors may rely on material flowing in a groove(s) while bleedingthrough a slit or ‘dam’ to wrap material any number of times into adesired shape. The dam can be modified by changing the length and/orthickness which determines how easily a fluid will flow through. Thesize of the groove can also be modified. By changing thesecharacteristics a balanced flow can be achieved. In general, thedeflectors work by making flow in the wrapping direction less torturousthan the direction of extrusion.

These deflectors have many benefits over other known deflectors.Deflectors which form a tubular shape normally function by mergingmaterial end to end to create a loop. Often a tubular product will burstwhere molten plastic was fused at a seam which would run straightthrough the thickness of the product. Wrapping deflectors act to windthis seam around the tube as it goes through the thickness of theproduct. A winded seam will result in increased burst strength as theseam is now a much more torturous path to split along. Another advantageof these deflector designs is that if a correctly oriented stream oflayers is being wrapped, every full revolution the material is wrappedwill act to multiply the number of layers through the thickness of thetube (or individual layer of the tube).

These multilayered/multi-component streams comprise so-called plasticsincluding but not limited topolyethylenes, polypropylenes, polystyrenes,polyvinyl chlorides, polytetrafluoroethylenes (PTFE), polysulfones,polyphenylene oxides, polybutylene terephthalates, polyvinylidenechlorides, polyethylene terephthalates, polystyrenes, polycyclohexanediethylene terephthalates, styrene-butadiene-acrylonitrile copolymer,polybutylene naphthalates, nylons such as nylon 11, nylon 12,polyimides, polyamides, polycarbonates, polyurethanes, polyacetals,polyether amides, polymethylmethacrylates, epoxys and polyester amides.Any other plastic or material used in this manner is considered anapparent extension of this invention.

Products made by these methods may have thousands of layers. Certainembodiments have 1-10 layers. Other embodiments have 10-100 layers. Yetother embodiments have 100-1000 layers and yet other embodiments have1000 to 100,000 even 1,000,000 layers.

Another embodiment of the invention relates to products containingfiller particles or fibers. Certain products contain filler particles orfibers aligned along the extrusion axis.

Another embodiment relates to products wherein the fibers are carbonfibers, more specifically carbon nanotubules.

Fibers include single fibers or a myriad of other arrangements. Someexemplary arrangements include but are not limited to yarns, a tow offibers or yarns, a weave, a non-woven, chopped fiber, a chopped fibermat (with random or ordered formats), or combinations of these formats.The chopped fiber mat or nonwoven may be stretched, stressed, ororiented to provide some alignment of the fibers within the nonwoven orchopped fiber mat, rather than having a random arrangement of fibers.

Fibers alignment can also be tailored by the application of externalforces such as magnetic fields.

Another embodiment of the present invention relates to extrudedmultilayer wrapped medical devices comprising one or more pharmaceuticalproduct(s) or drug substances (including mixtures thereof) layered withone or more biocompatible materials that control the time release of thedelivery of the drug substance.

Medical devices include but are not limited to catheters, stents,threads, cables (including fiber optic cables), pills, capsules,lozenges, tablets, implants, medical tubing, sheaths, clamps, sutures,tapes, sheets and endotracheal devices.

Another embodiment of the invention relates to a wrapped medical tubulardevice comprising: a polymeric tube containing small sized grains, nanoor micro-sized features and a drug substance.

Another embodiment of the present invention is directed to extrusionproducts possessing electrical properties. More specifically, theseextrusion products contain multilayers wherein one or more layerscontain electrical conducting materials and more specifically milli,micro or nanoparticle electrical conducting materials. An extrudablemetal could be used as a material to form conductive layers. Such metalscould also be used with compatible plastics to form insulated layers orpathways. Aspects of the disclosed embodiments are also directed tocreating and producing nanoparticle products usingmultilayers/multistreams (and also optionally wherein the layer may bein the milli, micro or nano dimension) to enhance the electricalproperties of the products. In one embodiment, each layer may becomprised of one or more elements that facilitate one or more of thelayers to conduct electricity.

One specific embodiment relates to an extruded multilayer polymerproduct comprising one or more layers possessing electrical properties.A more specific embodiment relates to a product wherein said one or morelayers are milli, micro or nano size, wherein said one or more layerscontain nanoparticle electrical conducting materials. More specificallywherein said product wherein said one or more electrical conductinglayers are layered between nonconducting layers.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate presently preferred embodiments ofthe present disclosure, and together with the general description givenabove and the detailed description given below, serve to explain theprinciples of the present disclosure. As shown throughout the drawings,like reference numerals designate like or corresponding parts.

FIG. 1 depicts an example of a wrapping deflector.

FIG. 2 depicts examples of products made by a deflector. FIG. 2( a)depicts a product with the seam winding around and through the productwhereas FIG. 2( b) depicts a product with seams straight through theproduct.

FIG. 3 illustrates a wrapping deflector.

FIG. 4 depicts the example where there are two grooves intertwined witheach groove wrapping around once.

FIG. 5 illustrates a product cross section made with many feeds andnested grooves with only minimal wrapping.

FIG. 6 illustrates a product produced wherein the grooves start to wrapbut are then bent back to the original starting angle as they headradially inwards.

FIG. 7( a) illustrates a deflector with grooves which could make aproduct of FIG. 7( b) wherein three input streams in which two areimbedded in the third.

FIGS. 8( a) and (b) demonstrate how materials flowing through deflectorscascade over themselves to form multiple layers.

FIG. 9( a) and (b) illustrate another variation of how materials flowthrough deflectors to form multiple layers.

FIGS. 10 (a) and 10 (b) offer two more example variations of a wrappingdeflector.

FIG. 11 illustrates the path of the grooves.

FIG. 12 illustrates a dam cut on the inside diameter of the deflector.

FIG. 13 illustrates how a deflector could be integrated with a tipcomponent.

FIG. 14 illustrates a plate with a near-ring groove.

FIG. 15 illustrates a deflector which would produce nested wrapping whenused in an assembly of multiple plates.

FIG. 16 illustrates how material flowing through two stacked deflectorswould look.

FIG. 17 illustrates several groove profiles.

DETAILED DESCRIPTION OF THE INVENTION

An example wrapping deflector is shown above in FIG. 1. In this example,a stream of material will travel spirally inwards while slowly flowingthrough the dam. The dam here is slowly getting shorter as the materialmakes its way through the groove. The shorter dam allows the material toflow through it easier which will help to form an even flow overdifferent portions of the dam. While this example is spiraling inwards,it could also be made to spiral outwards.

An example product made by such a deflector which shows the seam windingaround and through the product (FIG. 2( a)) next to a product with seamsstraight through the product (FIG. 2( b)).

FIG. 3 illustrates a wrapping deflector where the dam is widened asopposed to shortened in order to promote even flow along the length ofthe dam. The dam could also be located below the groove heading towardthe central axis before turning into a section similar to what is nowthe dam.

Multiple grooves could also be spirally nested within each other. Thesegrooves could hold the same materials or different materials. In FIG. 4,there are two grooves intertwined with each groove wrapping around once.Different numbers and lengths could be used to create a variety ofshapes.

FIG. 5 illustrates a product cross section made with many feeds andnested grooves with only minimal wrapping.

The grooves in a deflector could also take other forms than simplespirals. The grooves could form bends or wrap in areas besides thecentral axis.

FIG. 6 illustrates a product produced wherein the grooves start to wrapbut are then bent back to the original starting angle as they headradially inwards.

A deflector with grooves following the paths shown in FIG. 7( a) couldmake a product similar to FIG. 7( b). This example takes three inputstreams with two being imbedded in the third.

FIGS. 8( a) and (b) demonstrate how materials flowing through thesedeflectors cascade over themselves to form multiple layers. In thisexample the input stream is multilayered and wraps to form a four layertube. The number of layers in input streams could be from one tothousands and could also take a multi-component approach with multiplecross sections merged together.

Profile shapes could be formed by drawing in the shape with the grooveand maintaining separation of appendages or holes as the shapecompresses to its final size and shape. In some cases certain areas ofthe dam could be tightened or opened to change the amount of material indifferent parts of the cross section. Some parts of the dam could alsobe blocked off completely.

FIGS. 10( a) and 10(b) offer two more example variations of a wrappingdeflector. Rather than relying on a groove and dam to balance the flowof the material, the flow path moves forward while the material iswrapping to allow for the flow to expand in that direction. The flowpath could also widen along this process as seen FIG. 10 a to encouragethe wrapping.

The deflectors shown above maintain the separation while wrapping thematerials. In subsequent sections of the extrusion die, the materialwill merge onto itself to form the desired tubular shape.

FIG. 11 illustrates the path of the grooves.

FIG. 12 illustrates a dam cut on the inside diameter of the deflector.

FIG. 13 illustrates how a deflector would be integrated with a tipcomponent. In this embodiment, flow continues forwards in a groove whilewrapping and spilling over a dam. Each wrap would act to add anotherlayer to the annular stream being formed below.

Deflectors shown thus far are spirally wrapping shapes but they couldalso take stepped approaches to perform the wrapping. Such steppedapproaches could include forming a nearly closed ring for each step.Instead of merging back the beginning of its own ring (or another ringif there were nested streams), there would be a change in direction tostart another ring. The change in direction would depend on thedeflector style.

A stepped approach of the most recent style could consist of a series ofplates with grooves forming individual near-rings which would transitionto the next plate at the end of the ring.

FIG. 14 illustrates a plate with a near-ring groove. The dam acts tocreate flow radially inwards. The groove starts on the top left andcontinues until the path through the plate on the top right. This path,which could be angled, could then lead to the start of another ringwhich would create the wrapping effect in the product.

FIG. 15 illustrates a deflector which would produce nested wrapping whenused in an assembly of multiple plates. This plate would take two inputstreams.

FIG. 16 illustrates how material flowing through two stacked deflectorswould look.

The grooves in wrapping deflectors could be any shape. Many of theexamples shown in the figures are round or circular grooves. FIG. 17illustrates several groove profiles.

These wrapping deflectors could be used to create products consisting ofmultiple layers with each layer being made by its own deflector ormultiple materials could be used on the same deflector with separategrooves. A layer in this sense is distinct from sub layers in a streamof input material.

Thus, while there have been shown, described and pointed out,fundamental novel features of the invention as applied to the exemplaryembodiments thereof, it will be understood that various omissions andsubstitutions and changes in the form and details of devices and methodsillustrated, and in their operation, may be made by those skilled in theart without departing from the spirit or scope of the invention.Moreover, it is expressly intended that all combinations of thoseelements and/or method steps, which perform substantially the samefunction in substantially the same way to achieve the same results, arewithin the scope of the invention. Moreover, it should be recognizedthat structures and/or elements and/or method steps shown and/ordescribed in connection with any disclosed form or embodiment of theinvention may be incorporated in any other disclosed or described orsuggested form or embodiment as a general matter of design choice. It isthe intention, therefore, to be limited only as indicated by the scopeof the claims appended hereto.

1. A method for wrapping a stream of material or stream of layers ofmaterials comprising feeding a stream of material or stream of layers ofmaterials into a die containing a wrapping deflector which acts to wrapthe stream into a tubular or profile shape.
 2. A method according toclaim 1 wherein the wrapping deflector is a distribution groove with abalanced flow passage dispersing the molten plastic in an extrusion dieevenly within a tubular or profile extrusion channel.
 3. A methodaccording to claim 2, wherein the molten plastic in the extrusion dieforms a seam that is wound around and through the extrusion product. 4.A method according to claim 3, wherein the extruded product comprises awinded seam enhanced burst strength at the seam.
 5. A method forwrapping a stream of material or stream of layers of materials accordingto claim 1, wherein the die comprises multiple grooves spirally nestedwithin each other.
 6. A product comprising a wrapped stream of materialor stream of layers of materials in a tubular or profile shape.
 7. Aproduct according to claim 6 comprising a wrapped stream of material orstream of 2-12 layers of materials in a tubular or profile shape.
 8. Aproduct according to claim 7 wherein one or more of said layers is inthe micrometer thickness range.
 9. A product according to claim 7wherein one or more of said layers is in the nanometer thickness range.10. A product according to claim 6 comprising a wrapped stream ofmaterial or stream of 10-1000 layers of materials in a tubular orprofile shape.
 11. A product according to claim 10 wherein one or moreof said layers is in the micrometer thickness range.
 12. A productaccording to claim 10 wherein one or more of said layers is in thenanometer thickness range.
 13. A product according to claim 6 comprisinga wrapped stream of material or stream of 1000-100,00 layers ofmaterials in a tubular or profile shape.
 14. A product according toclaim 13 wherein one or more of said layers is in the micrometerthickness range.
 15. A product according to claim 13 wherein one or moreof said layers is in the nanometer thickness range.